package org.smart4j.chapter1.helper;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter1.util.CollectionUtil;
import org.smart4j.chapter1.util.PropsUtil;

public class DatabaseHelper {
	private static Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);
	private static final ThreadLocal<Connection> CONNECTION_HOLDER ;
	private static final QueryRunner QUERY_RUNNER;
	private static final BasicDataSource DATA_SOURCE;
	
	public static void executeSqlFile(String filePath){
		InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
		try{
			String sql;
			while((sql=reader.readLine()) != null){
				DatabaseHelper.executeUpdate(sql);
			}
		} catch(Exception e){
			LOGGER.error("execute sql file failure",e);
			throw new RuntimeException(e);
		}
		
	}
	
	static{
		CONNECTION_HOLDER = new ThreadLocal<Connection>();
		QUERY_RUNNER = new QueryRunner();
		Properties conf = PropsUtil.loadProps("config.properties");
		String driver = conf.getProperty("jdbc.driver");
		String url = conf.getProperty("jdbc.url");
		String username = conf.getProperty("jdbc.username");
		String password = conf.getProperty("jdbc.password");
		DATA_SOURCE = new BasicDataSource();
		DATA_SOURCE.setDriverClassName(driver);
		DATA_SOURCE.setUrl(url);
		DATA_SOURCE.setUsername(username);
		DATA_SOURCE.setPassword(password);
//		try{
//			Class.forName(DRIVER);
//		}catch (ClassNotFoundException e) {
//			LOGGER.error("can not load jdbc driver",e);
//		}
	}
	
	public static Connection getConnection(){
		Connection conn = CONNECTION_HOLDER.get();
		if(conn == null){
			try{
				conn = DATA_SOURCE.getConnection();
			}catch(SQLException e){
				LOGGER.error("get connection failure",e);
				throw new RuntimeException(e);
			} finally{
				CONNECTION_HOLDER.set(conn);
			}
		}
		return conn;
	}
	
	/**
	 * 使用线程池来管理不需要close方法
	 */
//	public static void closeConnection(){
//		Connection conn = CONNECTION_HOLDER.get();
//		if(conn != null){
//			try {
//				conn.close();
//			} catch (SQLException e) {
//				LOGGER.error("close connection failure",e);
//				throw new RuntimeException(e);
//			} finally{
//				CONNECTION_HOLDER.remove();
//			}
//		}
//	}
	
	
	
	public static <T> List<T> queryEntityList(Class<T> class1,String sql,Object... params){
		List<T> entityList;
		try {
			Connection conn = getConnection();
			entityList = QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(class1),params);
		} catch (SQLException e) {
			LOGGER.error("query entity list failure",e);
			throw new RuntimeException(e);
		} 
//		finally {
//			closeConnection();
//		}
		return entityList;
	}
	
	/**
	 * 查询实体
	 * @param entityClass
	 * @param sql
	 * @param params
	 * @return
	 */
	public static <T> T queryEntity(Class<T> entityClass,String sql,Object... params){
		T entity;
		try{
			Connection conn = getConnection();
			entity = QUERY_RUNNER.query(conn, sql, new BeanHandler<T>(entityClass),params);
		} catch(SQLException e){
			LOGGER.error("query entity failure",e);
			throw new RuntimeException(e);
		} 
//		finally{
//			closeConnection();
//		}
		return entity;
	}
	
	/**
	 * 执行查询语句
	 * @param sql
	 * @param params
	 * @return
	 */
	public static List<Map<String,Object>> executeQuery(String sql,Object...params){
		List<Map<String,Object>> result;
		try{
			Connection conn = getConnection();
			result = QUERY_RUNNER.query(conn, sql, new MapListHandler(), params);
		} catch(Exception e){
			LOGGER.error("execute query failure",e);
			throw new RuntimeException(e);
		} 
//		finally{
//			closeConnection();
//		}
		return result;
	}
	
	/**
	 * 执行更新语句 包括update insert delete
	 * @param sql
	 * @param params
	 * @return
	 */
	public static int executeUpdate(String sql ,Object...params){
		int rows = 0;
		try{
			Connection conn = getConnection();
			rows = QUERY_RUNNER.update(conn, sql, params);
		} catch(SQLException e){
			LOGGER.error("execute update failure",e);
			throw new RuntimeException(e);
		} 
//		finally{
//			closeConnection();
//		}
		return rows;
	}
	
	/**插入操作
	 * @param entityClass
	 * @param fieldMap
	 * @return
	 */
	public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
		if(CollectionUtil.isEmpty(fieldMap)){
			LOGGER.error("can not insert entity:fieldMap is empty");
			return false;
		}
		
		String sql = "INSERT INTO " + getTableName(entityClass);
		StringBuilder columns = new StringBuilder("(");
		StringBuilder values = new StringBuilder("(");
		for(String fieldName:fieldMap.keySet()){
			columns.append(fieldName).append(", ");
			values.append("?, ");
		}
		columns.replace(columns.lastIndexOf(", "), columns.length(), ")");
		values.replace(values.lastIndexOf(","), values.length(), ")");
		sql += columns + " VALUES " + values;
		Object[] params = fieldMap.values().toArray();
		return executeUpdate(sql, params) == 1;
	}

	/**更新实体
	 * @param entityClass
	 * @param id
	 * @param fieldMap
	 * @return
	 */
	public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap){
		if(CollectionUtil.isEmpty(fieldMap)){
			LOGGER.error("can not update entity: fieldMap is empty");
			return false;
		}
		String sql = "UPDATE " + getTableName(entityClass) + " SET ";
		StringBuilder columns = new StringBuilder();
		for(String fieldName:fieldMap.keySet()){
			columns.append(fieldName).append("=?, ");
		}
		sql += columns.substring(0,columns.lastIndexOf(", ")) + " WHERE id=?";
		List<Object> paramList = new ArrayList<Object>();
		paramList.addAll(fieldMap.values());
		paramList.add(id);
		Object[] params = paramList.toArray();
		return executeUpdate(sql,params) == 1;
	}
	
	/**删除实体
	 * @param entityClass
	 * @param id
	 * @return
	 */
	public static <T> boolean deleteEntity(Class<T> entityClass,long id){
		String sql = "DELETE FROM " + getTableName(entityClass) + " WHERE id = ?";
		return executeUpdate(sql,id) == 1;
	}
	
	private static String getTableName(Class<?> entityClass) {
		return entityClass.getSimpleName().toLowerCase();
	}
	
	
}
